THE LYMPHATIC SYSTEM

                                      THE LYMPHATIC SYSTEM 

It is additional drainage system .

 it carries the fluid which comes out from the blood vessels but fails to go back to the venous end .

 it consist of

• ·         Lymph
• ·         Lymph node
• ·         Lymphatic vessels 
• ·         Lymphatic organs such as spleen and thymus
• ·         Lymphoid tissue like tonsil

Function system

·         Helps in the absorption of fat and fat soluble substance from digestive system

·         Returns fluid from the extra vascular compartment back to general circulation

·         Lymphocytes produced from lymphatic organs provide immunity

Lymph

·         It appears milky in the intestine due to presence of fat in it

·         Plasma proteins which have escaped from blood vessels will be transported to the blood stream by lymph

·         Lymph carries dead bacteria and cell break down products to lymph nodes for destruction and elimination

Lymph vessels

·         They are similar to blood capillaries in their structure having a layer of endoethelial   cell. Lymph capillaries from interstitial space , join to from large lymph vessels

·         Central nervous system bones and superficial layer of the skin do not have lymphatic supply

Larger lymph vessels

·         Lymph is moved in the lymph vessels by contraction of muscle present in their walls (lymph pump)

·         Movement of lymph is also facilitated by the contraction of muscle around the vessel

·         Larger lymph join to from thoracic duct and right lymphatic duct which drains in  to subclavian veins .

THORACIC DUCT

v  It begins at the level of first two lumbar vertebrae.

v  It opens into left subclavin vein at the root of neck.

v  It drains lymph from both legs,pelvic,abdominal structures,left of thorax, left arm, head and neck.

v  Thoracic duct measures about 40 cm.

RIGHT LYMPHATIC DUCT:

 It lies at the roof of neck drains into right subclavian vein.

It drains from right arm, right of thorax, head and neck.

LYMPH NODES:

§  Lymph nodes are oval in shape.they are present along the lymphatic vessels.

§  Lymph nodes are arranged in superficial & deep group.

§  Lymph node has a concave surface called hilum.blood vessels enter & the lymph node through hilum.

§  Each lymph node has four to five afferent lymph vessels & a single efferent vessel.

§  Cut section of lymph node shows on outer fibrous tissue capsule.

§  Capsule invaginates into the substance of node forming trabeculae.

§  Substance of lymph node is made up of reticular & lymphatic tissue width macrophages & lymphocytes.

§  Lymph passes through multiple nodes before in reaches venous blood.

Situation of lymph node:

1.       Cervical nodes – head and neck

2.       Axillary nodes – upper limbs & breast

3.       Abdominal & pelvic nodes – pelvic & abdominal organs

4.       Mediastinal nodes & those close to large airways – structures organs and tissues from thoracic cavity

5.       Superficial & deep groop of inguinal nodes – lower limbs

Function of lymph nodes:

ü  Filter particle present in lymph.

ü  Organic materials are destroyed by macrophages and antibodies.

ü  Insoluble particles are engulfed by the macrophages.

ü  Help in proliferation of activated T & B lymphocytes.